Fourteen infertile males (age 24-45 years; married over 2 years) with idiopathic oligospermia (sperm count less than 40 millions/ml) were investigated for the effect of oral zinc sulphate (220 mg) for 4 months on their serum and seminal zinc levels, and seminal parameters. With zinc administration serum zinc levels remained essentially unaffected, however, seminal zinc levels increased significantly. There was significant improvement in sperm count, number of progressively motile and normal spermatozoa, and acid phosphates activity. Wives of 3 patients conceived. Observations suggest that zinc has potential to be used in male infertility. However, further studies are warranted.